Protective film forming composition having a diol structure

ABSTRACT

A protective film-forming composition which protects against a semiconductor wet etching solution, contains a solvent and a compound or polymer thereof containing at least one pair including two adjacent hydroxyl groups in a molecule thereof, and forms a protective film which can quickly be removed by dry etching and exhibits excellent resistance against a semiconductor wet etching solution during the lithographic process when producing semiconductors; a method for producing a resist pattern-equipped substrate which uses the protective film; and a method for producing a semiconductor device.

TECHNICAL FIELD

The present invention relates to a composition for forming a protectivefilm having excellent resistance to a wet etching liquid forsemiconductor, preferably a basic aqueous hydrogen peroxide solution ina lithography process in the production of a semiconductor. In addition,the present invention relates to a method for forming a resist patternusing the protective film, and a method for producing a semiconductordevice.

BACKGROUND ART

A lithography process in the production of a semiconductor has beenwidely known in which a resist underlying film is formed between asubstrate and a resist film formed on the substrate, forming a resistpattern having a desired form.

Patent Literature 1 discloses an antireflection coating compositionwhich comprises a polymer having a glycidyl group and a polymer havingan aromatic group substituted with, e.g., a hydroxy group, and which isused together with a photoresist formed as an overcoat, and a method inwhich a photoresist underlying film is formed using the antireflectioncoating composition, and subjected to exposure, development, andpatterning.

Patent Literature 2 discloses a method which comprises applying acomposition comprising a resin containing an epoxy reactive group, suchas a hydroxy group, and a crosslinkable resin containing an epoxy grouponto a substrate, and forming a photoresist layer on the appliedcomposition, forming a photoresist relief.

CITATION LIST Patent Literature

Patent Literature 1: JP 2017-107185 A

Patent Literature 2: JP 2017-187764 A

SUMMARY OF INVENTION Technical Problem

In the case where a resist underlying film is used as an etching maskand a substrate is processed by wet etching, the resist underlying filmis required to function as an excellent mask with respect to the wetetching liquid used during processing of the substrate. Further, whenthe unnecessary resist underlying film remaining after the wet etchingis removed by dry etching, the resist underlying film is needed to havesuch a fast etching rate (high etching rate) that the resist underlyingfilm can be quickly removed by dry etching so as not to damage thesubstrate.

Conventionally, for obtaining a film exhibiting a resistance to SC-1(ammonia-hydrogen peroxide solution) which is a kind of wet etchingchemical liquid, a method of applying gallic acid as an additive to thefilm has been used.

Further, it has been known that a catechol structure exhibits animprovement effect for the resistance to a wet etching liquid forsemiconductor (Patent Literatures 1 and 2), but the catechol structurecontains an aromatic group, and therefore it has been difficult for thecatechol structure to achieve both excellent resistance to a wet etchingliquid and high etch rate.

An object of the present invention is to solve the above-mentionedproblems.

Solution to Problem

The present invention includes the followings.

-   -   [1] A composition for forming a protective film against a wet        etching liquid for semiconductor, the protective film forming        composition comprising a solvent and a compound containing in        the molecule thereof at least a pair of two hydroxy groups        adjacent to each other, or a polymer thereof    -   [2] The protective film forming composition according to item        [1] above, wherein the two hydroxy groups adjacent to each other        constitute a 1,2-ethanediol structure.    -   [3] The protective film forming composition according to item        [1] above, wherein the compound has a partial structure        represented by the following formula (1) or formula (2):

wherein, in formula (1) and formula (2), each of R¹, R², and R³represents a hydrogen atom, or an alkyl group having 1 to 10 carbonatoms or an aryl group having 6 to 40 carbon atoms, each of the groupsoptionally being substituted, and R¹ and R² or R³ optionally togetherform a ring, and Z¹ and Z² represent a monovalent organic group.

-   -   [4] The protective film forming composition according to item        [3] above, wherein, in formula (1) and formula (2), R¹, R², and        R³ are a hydrogen atom.    -   [5] The protective film forming composition according to any one        of items [1] to [4] above, which further comprises a        crosslinking catalyst.    -   [6] The protective film forming composition according to any one        of items [1] to [5] above, which further comprises a        crosslinking agent.    -   [7] The protective film forming composition according to any one        of items [1] to [6] above, which further comprises a surfactant.    -   [8] A protective film which is a baked product of an applied        film of the protective film forming composition according to any        one of items [1] to [7] above.    -   [9] A method for producing a substrate having a resist pattern,        comprising the steps of applying the protective film forming        composition according to any one of items [1] to [7] above onto        a semiconductor substrate and baking the applied composition to        form a protective film as a resist underlying film, which is        used for producing a semiconductor.    -   [10] A method for producing a semiconductor device, comprising        the steps of:

-   forming a protective film on a semiconductor substrate optionally    having an inorganic film formed on the surface thereof using a    protective film forming composition according to any one of claims 1    to 7;

-   forming a resist pattern on the protective film;

-   subjecting the protective film to dry etching using the formed    resist pattern as a mask so as to expose a surface of the inorganic    film or the semiconductor substrate; and,

-   using the dry-etched protective film as a mask, subjecting the    inorganic film or the semiconductor substrate to wet etching with a    wet etching liquid for semiconductor and to washing.

Advantageous Effects of Invention

In the present invention, by introducing a 1,2-ethanediol structure,which is aliphatic, into the polymer used in the composition, theprotective film formed from such a composition can exhibit not only aresistance to a wet etching liquid for semiconductor but also a highetch rate.

DESCRIPTION OF EMBODIMENTS Protective Film Forming Composition

The protective film forming composition of the present invention forforming a protective film against a wet etching liquid for semiconductorcomprises a solvent and a compound containing in the molecule thereof atleast a pair of two hydroxy groups adjacent to each other, or a polymerthereof. The components of the composition are individually describedbelow.

Compound Containing in the Molecule Thereof at Least a Pair of TwoHydroxy Groups Adjacent to Each Other

The two hydroxy groups adjacent to each other preferably constitute a1,2-ethanediol structure.

The 1,2-ethanediol structure is preferably a partial structurerepresented by the following formula (1) or formula (2):

wherein, in formula (1) and formula (2), each of R¹, R², and R³represents a hydrogen atom, or an alkyl group having 1 to 10 carbonatoms or an aryl group having 6 to 40 carbon atoms, each of the groupsoptionally being substituted, Z¹ and Z² represent a monovalent organicgroup, and R¹ and R² or R³ optionally together form a ring.

Examples of optionally substituted alkyl groups having 1 to 10 carbonatoms include a methyl group, an ethyl group, a n-propyl group, ani-propyl group, a cyclopropyl group, a n-butyl group, an i-butyl group,a s-butyl group, a t-butyl group, a cyclobutyl group, a1-methyl-cyclopropyl group, a 2-methyl-cyclopropyl group, a n-pentylgroup, a 1-methyl-n-butyl group, a 2-methyl-n-butyl group, a3-methyl-n-butyl group, a 1,1-dimethyl-n-propyl group, a1,2-dimethyl-n-propyl group, a 2,2-dimethyl-n-propyl group, a1-ethyl-n-propyl group, a cyclopentyl group, a 1-methyl-cyclobutylgroup, a 2-methyl-cyclobutyl group, a 3-methyl-cyclobutyl group, a1,2-dimethyl-cyclopropyl group, a 2,3-dimethyl-cyclopropyl group, a1-ethyl-cyclopropyl group, a 2-ethyl-cyclopropyl group, a n-hexyl group,a 1-methyl-n-pentyl group, a 2-methyl-n-pentyl group, a3-methyl-n-pentyl group, a 4-methyl-n-pentyl group, a1,1-dimethyl-n-butyl group, a 1,2-dimethyl-n-butyl group, a1,3-dimethyl-n-butyl group, a 2,2-dimethyl-n-butyl group, a2,3-dimethyl-n-butyl group, a 3,3-dimethyl-n-butyl group, a1-ethyl-n-butyl group, a 2-ethyl-n-butyl group, a1,1,2-trimethyl-n-propyl group, a 1,2,2-trimethyl-n-propyl group, a1-ethyl-1-methyl-n-propyl group, a 1-ethyl-2-methyl-n-propyl group, acyclohexyl group, a 1-methyl-cyclopentyl group, a 2-methyl-cyclopentylgroup, a 3-methyl-cyclopentyl group, a 1-ethyl-cyclobutyl group, a2-ethyl-cyclobutyl group, a 3-ethyl-cyclobutyl group, a1,2-dimethyl-cyclobutyl group, a 1,3-dimethyl-cyclobutyl group, a2,2-dimethyl-cyclobutyl group, a 2,3-dimethyl-cyclobutyl group, a2,4-dimethyl-cyclobutyl group, a 3,3-dimethyl-cyclobutyl group, a1-n-propyl-cyclopropyl group, a 2-n-propyl-cyclopropyl group, a1-i-propyl-cyclopropyl group, a 2-i-propyl-cyclopropyl group, a1,2,2-trimethyl-cyclopropyl group, a 1,2,3-trimethyl-cyclopropyl group,a 2,2,3-trimethyl-cyclopropyl group, a 1-ethyl-2-methyl-cyclopropylgroup, a 2-ethyl-1-methyl-cyclopropyl group, a2-ethyl-2-methyl-cyclopropyl group, and a 2-ethyl-3-methyl-cyclopropylgroup.

Examples of aryl groups having 6 to 40 carbon atoms include a phenylgroup, an o-methylphenyl group, a m-methylphenyl group, a p-methylphenylgroup, an o-chlorophenyl group, a m-chlorophenyl group, a p-chlorophenylgroup, an o-fluorophenyl group, a p-fluorophenyl group, ano-methoxyphenyl group, a p-methoxyphenyl group, a p-nitrophenyl group, ap-cyanophenyl group, an α-naphthyl group, a β-naphthyl group, ano-biphenylyl group, a m-biphenylyl group, a p-biphenylyl group, a1-anthryl group, a 2-anthryl group, a 9-anthryl group, a 1-phenanthrylgroup, a 2-phenanthryl group, a 3-phenanthryl group, a 4-phenanthrylgroup, and a 9-phenanthryl group.

Examples of substituents for the above alkyl groups and aryl groupsinclude halogen atoms (fluorine, chlorine, bromine, and iodine), a nitrogroup, a cyano group, an amino group, a hydroxy group, a carbonyl group,and a carbonyloxy group, but the substituent is not limited to these.

In formula (1) and formula (2), R¹, R², and R³ are preferably a hydrogenatom.

Monovalent Organic Group

With respect to the monovalent organic group, there is no particularlimitation. The monovalent organic group may be one which is derivedfrom a polymer or an oligomer, or one which is derived from alow-molecular weight compound.

Monovalent Organic Group Ferived From a Polymer

By employing an organic group derived from a polymer, it is possible tocontrol, for example, the dry etching rate (reduction of the filmthickness per unit time), attenuation coefficient, and refractive indexof a resist underlying film formed from the protective film formingcomposition of the present invention.

With respect to the polymer, there is no particular limitation, andvarious types of organic polymers may be used. For example, an additionpolymerization polymer, a polycondensation polymer, or a ring-openingpolymerization polymer, such as a polyester, a polystyrene, a polyimide,an acrylic polymer, a methacrylic polymer, a polyvinyl ether, a phenolicnovolak, a naphthol novolak, a polyether, a polyamide, or apolycarbonate, may be used.

Examples of such organic polymers include addition polymerizationpolymers comprising, as structural units, an addition-polymerizablemonomer, such as benzyl acrylate, benzyl methacrylate, phenyl acrylate,naphthyl acrylate, anthryl methacrylate, anthrylmethyl methacrylate,styrene, hydroxystyrene, benzyl vinyl ether, or N-phenylmaleimide, andpolycondensation polymers, such as a phenolic novolak and a naphtholnovolak.

When an addition polymerization polymer is used as the above-mentionedorganic polymer, the polymer may be either a homopolymer or a copolymer.In the production of an addition polymerization polymer, anaddition-polymerizable monomer is used. Examples of theaddition-polymerizable monomers include acrylic acid, methacrylic acid,an acrylate compound, a methacrylate compound, an acrylamide compound, amethacrylamide compound, a vinyl compound, a styrene compound, amaleimide compound, maleic anhydride, and acrylonitrile.

Examples of the acrylate compounds include methyl acrylate, ethylacrylate, normalhexyl acrylate, isopropyl acrylate, cyclohexyl acrylate,benzyl acrylate, phenyl acrylate, anthrylmethyl acrylate, 2-hydroxyethylacrylate, 3-chloro-2-hydroxypropyl acrylate, 2-hydroxypropyl acrylate,2,2,2-trifluoroethyl acrylate, 2,2,2-trichloroethyl acrylate,2-bromoethyl acrylate, 4-hydroxybutyl acrylate, 2-methoxyethyl acrylate,tetrahydrofurfuryl acrylate, 2-methyl-2-adamantyl acrylate,5-acryloyloxy-6-hydroxynorbornene-2-carboxylic-6-lactone,3-acryloxypropyltriethoxysilane, and glycidyl acrylate.

Examples of the methacrylate compounds include methyl methacrylate,ethyl methacrylate, normalhexyl methacrylate, isopropyl methacrylate,cyclohexyl methacrylate, benzyl methacrylate, phenyl methacryl ate,anthrylmethyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylmethacrylate, 2,2,2-trifluoroethyl methacrylate, 2,2,2-trichloroethylmethacrylate, 2-bromoethyl methacrylate, 4-hydroxybutyl methacrylate,2-methoxyethyl methacrylate, tetrahydrofurfuryl methacrylate,2-methyl-2-adamantyl methacrylate,5-methacryloyloxy-6-hydroxynorbornene-2-carboxylic-6-lactone,3-methacryloxypropyltriethoxysilane, glycidyl methacryl ate, 2-phenylethyl methacrylate, hydroxyphenyl methacrylate, and bromophenylmethacrylate.

Examples of the acrylamide compounds include acrylamide, N-methylacrylamide, N-ethylacrylamide, N-benzyl acrylamide, N-phenylacrylamide,N,N-dimethyl acrylamide, and N-anthrylacrylamide.

Examples of the methacrylamide compounds include methacrylamide,N-methylmethacryl amide, N-ethylmethacrylamide, N-benzylmethacrylamide,

N-phenylmethacrylamide, N,N-dimethylmethacrylamide, and N-anthrylacrylamide.

Examples of the vinyl compounds include vinyl alcohol, 2-hydroxyethylvinyl ether, methyl vinyl ether, ethyl vinyl ether, benzyl vinyl ether,vinyl acetate, vinyltrimethoxysilane, 2-chloroethyl vinyl ether,2-methoxyethyl vinyl ether, vinylnaphthalene, and vinylanthracene.

Examples of the styrene compounds include styrene, hydroxystyrene,chlorostyrene, bromostyrene, methoxystyrene, cyanostyrene, and acetylstyrene.

Examples of the maleimide compounds include maleimide,N-methylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide,N-benzylmaleimide, and N-hydroxyethylmaleimide.

When a polycondensation polymer is used as the polymer, examples of suchpolymers include polycondensation polymers of a glycol compound and adicarboxylic acid compound.

Examples of the glycol compounds include diethylene glycol,hexamethylene glycol, and butylene glycol.

Examples of the dicarboxylic acid compounds include aliphaticdicarboxylic acids and aromatic dicarboxylic acids, such as succinicacid, 2,2-dimethylsuccinic acid, adipic acid, terephthalic acid,isophthalic acid, phthalic acid, 3,3′-dithiodipropionic acid, tartaricacid, malic acid, and maleic anhydride.

Further examples include polyesters, polyamides, and polyimides, such aspolypyromellitimide, poly(p-phenyleneterephthalamide), polybutyleneterephthalate, and polyethylene terephthalate.

When a ring-opening polymerization polymer is used as the polymer,examples of such polymers include polycondensation polymers of a diepoxycompound and a dicarboxylic acid compound.

Examples of diepoxy compounds include compounds, such as sorbitolpolyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritolpolyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidylether, trimethylolpropane polyglycidyl ether, neopentyl glycoldiglycidyl ether, 1,6-hexanediol diglycidyl ether, and compoundsrepresented by the following formulae [3-1] to [3-16]:

Examples of the dicarboxylic acid compounds include the above-mentioneddicarboxylic acid compounds.

As the polymer, a polymer having a weight average molecular weight of,for example, 1,000 to 100,000, or 1,500 to 50,000, or 2,000 to 30,000,or 3,000 to 20,000 may be used.

The polymer is preferably one having a structure of the followingformula (10):

[Chemical formula 4]

wherein A represents a direct bond or —C(═O)—, and Ar represents abenzene ring, a naphthalene ring, or an anthracene ring, which isoptionally substituted with an alkyl group having 1 to 6 carbon atoms, ahalogen atom, a hydroxy group, a carboxyl group, an amino group, analkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to6 carbon atoms, a cyano group, an acetyl group, an acetyloxy group, analkoxycarbonyl group having 1 to 6 carbon atoms, a nitro group, anitroso group, an amide group, an imide group, an alkoxysulfonyl grouphaving 1 to 6 carbon atoms, or a sulfonamide group.

Examples of alkyl groups in formula (10) include a methyl group, anethyl group, a n-butyl group, a t-butyl group, an isopropyl group, and acyclohexyl group, examples of halogen atoms include a fluorine atom, achlorine atom, a bromine atom, and an iodine atom, examples of alkoxygroups include a methoxy group, an ethoxy group, and a butoxy group,examples of alkylthio groups include a methylthio group, an ethylthiogroup, and a butylthio group, examples of alkoxycarbonyl groups includea methoxycarbonyl group, an ethoxycarbonyl group, and anisopropoxycarbonyl group, and examples of alkoxysulfonyl groups includea methoxysulfonyl group and an ethoxysulfonyl group.

The polymer may be produced by, for example, the method described inJapanese Patent No. 5041175.

It is desired that the content of the aromatic group in the polymer isappropriately suppressed to a predetermined value according to therequired etch rate.

Monovalent Organic Group Derived From a Low-Molecular Weight Compound

With respect to the low-molecular weight compound from which themonovalent organic group is derived, there is no particular limitation,but, considering a risk of volatilization of the compound during thebaking, preferred is a compound having a molecular weight of 300 ormore. The upper limit of the molecular weight of the compound is, forexample, 999. Specific preferred examples of the compounds are shownbelow. Symbol * indicates a bonding site.

Further, the monovalent organic group may be one derived from theabove-mentioned low-molecular weight compound having a spacer addedthereto. Examples of spacers include —CH—, —(CH₂)_(n), (n=1 to 20),—CH═CH—, —CH≡CH—, —N═N—, —NH—, —NHR—, —NHCO—, —NRCO—, —S—, —COO—, —CO—,—CO—, —CH═N—, and phenylene and a combination thereof. Two or morespacers may be linked together.

Specific Preferred Examples of the Compound Having a Partial StructureRepresented by Formula (1)

Preferred examples of the compound having a partial structurerepresented by formula (1) are as shown below.

The polymer having a partial structure represented by formula (1)includes structural units represented by the following formulae (A-1) to(A-12).

The molar ratio of the unit structure having a partial structure offormula (1) or formula (2) to the whole of the polymer having a partialstructure represented by formula (1) or formula (2) ranges 1 to 100% bymole, preferably 10 to 100% by mole. With respect to the unit structurehaving a partial structure represented by formula (1) or formula (2),one type of or two or more types of the unit structures may be used.

When the polymer is a copolymer having a unit structure having a partialstructure represented by the formula other than formula (1) or formula(2), the molar ratio of such a unit structure corresponds to the molarratio of the portion remaining after removing the portion of the unitstructure having a partial structure represented by formula (1) orformula (2) to the whole of the copolymer. In the above case, withrespect to the unit structure having a partial structure represented bythe formula other than formula (1) or formula (2), one type of or two ormore types of the unit structures may be used.

Further, examples of the compound or polymer having a partial structurerepresented by formula (1) above include a reaction product (D) obtainedfrom an epoxy compound or resin represented by formula (B) below and aproton generating compound represented by formula (C) below, and aring-opening reaction product (E) of an epoxy compound or resin (C).

Examples of epoxy compounds (B) include a glycidyl ether compound, aglycidyl ester compound, a glycidyl group-containing isocyanurate, anepoxycyclohexyl compound, an epoxy group-substituted cyclohexylcompound, and resins thereof. Examples of epoxy compounds (B) used inthe present invention include the followings.

The compound of formula (B-1) is available under the trade name:TEPIC-SS, manufactured by Nissan Chemical Corporation.

The compound of formula (B-2) is available under the trade name:MA-DGIC, manufactured by Shikoku Chemicals Corporation.

The compound of formula (B-3) is available under the trade name: EX-411,manufactured by Nagase Chemtex Corporation.

The compound of formula (B-4) is available under the trade name: EX-521,manufactured by Nagase Chemtex Corporation.

The compound of formula (B-7) is available under the trade name:RE-810NM, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-8) is available under the trade name: BATG,manufactured by Showa Denko K.K.

The compound of formula (B-9) is available under the trade name: EX-711,manufactured by Nagase Chemtex Corporation.

The compound of formula (B-10) is available under the trade name:YD-4032D, manufactured by DIC Corporation.

The compound of formula (B-11) is available under the trade name:HP-4770, manufactured by DIC Corporation.

The compound of formula (B-12) is available under the trade name:YH-434L, manufactured by Nippon Steel & Sumikin Chemical Co., Ltd.

The compound of formula (B-13) is available under the trade name:EPICLON HP-4700, manufactured by DIC Corporation.

The compound of formula (B-14) is available under the trade name: TEP-G,manufactured by Asahi Yukizai Corporation.

The compound of formula (B-15) is trade name: Epolead GT401,manufactured by Daicel Corporation, wherein each of a, b, c, and d is 0or 1, and a +b +c+d=1.

The compound of formula (B-16) is available under the trade name:EHPE-3150, manufactured by Daicel Corporation.

The compound of formula (B-17) is available under the trade name:HP-7200L, manufactured by DIC Corporation.

The compound of formula (B-18) is available under the trade name:EPPN-201, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-19) is available under the trade name:ECN-1229, manufactured by Asahi Kasei Epoxy Co., Ltd.

The compound of formula (B-20) is available under the trade name:EPPN-501H, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-21) is available under the trade name:NC-2000L, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-22) is available under the trade name:NC-3000L, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-23) is available under the trade name:NC-7000L, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-24) is available under the trade name:NC-7300L, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-25) is available under the trade name:NC-3500, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-26) is available under the trade name:EPICLON HP-5000, manufactured by DIC Corporation.

The compound of formula (B-27) is available under the trade name:FAE-2500, manufactured by Nippon Kayaku Co., Ltd.

The compound of formula (B-28) is available under the trade name:NC-6000, manufactured by Nippon Kayaku Co., Ltd.

Examples of proton generating compounds (C) include compounds capable ofreacting with an epoxy group, such as a phenolic hydroxygroup-containing compound, a carboxylic acid-containing compound, anamine-containing compound, a thiol-containing compound, and animide-containing compound. Examples of proton generating compounds (C)used in the present invention include the followings.

Specific examples of reaction product (D) of epoxy compound or resin (B)and proton generating compound (C), which is the compound or polymerhaving a partial structure represented by formula (1) above, include thefollowings, but reaction product (D) is not limited to these compounds.

Specific examples of ring-opening reaction product (E) of an epoxycompound, which is the compound or polymer having a partial structurerepresented by formula (1) above, include the followings, butring-opening reaction product (E) is not limited to these compounds.

Further, the compound or polymer having a partial structure representedby formula (1) above is a reaction product (F) of a phenolic hydroxygroup-containing compound, a carboxylic acid-containing compound, anamine-containing compound, a thiol-containing compound, animide-containing compound, or a resin thereof and glycidol. Specificexamples of reaction product (F) include the followings, but reactionproduct (F) is not limited to these compounds.

An example of the compound or polymer having a partial structurerepresented by formula (2) above includes a reaction product (G)obtained from the epoxy compound or resin represented by formula (B)above and a proton generating compound represented by formula (H) below,and, examples of proton generating compounds (H) used in the presentinvention include the followings.

Further, specific examples of reaction product (G) obtained from theepoxy compound or resin (B) and proton generating compound (H), which isthe compound or polymer having a partial structure represented byformula (2) above, include the followings, but reaction product (G) isnot limited to these compounds.

Crosslinking Agent

The resist underlying film forming composition of the present inventionmay contain a crosslinking agent component. Examples of the crosslinkingagents include those of a type of melamine, substituted urea, or apolymer thereof. Preferred is a crosslinking agent having at least twocrosslinking forming substituents, and examples include compounds, suchas methoxymethylated glycoluril, butoxymethylated glycoluril,methoxymethylated melamine, butoxymethylated melamine, methoxymethylatedbenzoguanamine, butoxymethylated benzoguanamine, methoxymethylated urea,butoxymethylated urea, methoxymethylated thiourea, and methoxymethylatedthiourea. Further, a condensation product of the above compound may beused.

As the crosslinking agent, a crosslinking agent having a high heatresistance may be used. With respect to the crosslinking agent having ahigh heat resistance, a compound containing in the molecule thereof acrosslinking forming substituent having an aromatic ring (for example, abenzene ring or a naphthalene ring) may be used.

Examples of the compounds include compounds having a partial structureof formula (5-1) below, and polymers or oligomers having repeating unitsof formula (5-2) below.

The above-mentioned R¹¹, R¹², R¹³, and R¹⁴ are a hydrogen atom or analkyl group having 1 to 10 carbon atoms, and, with respect to the alkylgroup, those mentioned above as examples of alkyl groups may be used.

m1 satisfies the relationship: 1≤ml≤6−m2, m2 satisfies the relationship:1 m2≤5, m3 satisfies the relationship: 1≤m3≤4−m2, and m4 satisfies therelationship: 1≤m4≤<3.

Examples of the compounds, polymers, and oligomers of the formulae (5-1)and (5-2) are shown below.

The above-mentioned compounds are available as products of Asahi YukizaiCorporation and Honshu Chemical Industry Co., Ltd. For example, amongthe above-mentioned crosslinking agents, the compound of formula (6-22)is available under the trade name: TMOM-BP, manufactured by AsahiYukizai Corporation.

The amount of the crosslinking agent added varies depending on, forexample, the application solvent used, the substrate used, the requiredsolution viscosity, or the required film form, but it ranges 0.001 to80% by weight, preferably 0.01 to 50% by weight, further preferably 0.1to 40% by weight, based on the weight of the solid of the protectivefilm forming composition. The crosslinking agent possibly causes acrosslinking reaction due to self-condensation, but, when acrosslinkable substituent is present in the above-mentioned polymer inthe present invention, the crosslinking agent and the crosslinkablesubstituent may together cause a crosslinking reaction.

Crosslinking Catalyst

The protective film forming composition of the present invention maycontain, as an optional component, a crosslinking catalyst foraccelerating the crosslinking reaction. As the crosslinking catalyst, anacidic compound, a basic compound, or a compound capable of generatingan acid or a base due to heat may be used, but preferred is acrosslinking acid catalyst. As the acidic compound, a sulfonic acidcompound or a carboxylic acid compound may be used, and, as the compoundcapable of generating an acid due to heat, a thermal acid generator maybe used.

Examples of sulfonic acid compounds or carboxylic acid compounds includep-toluenesulfonic acid, trifluoromethanesulfonic acid, pyridiniumtrifluoromethanesulfonate, pyridinium p-toluenesulfonate, salicylicacid, camphorsulfonic acid, 5-sulfosalicylic acid,4-chlorobenzenesulfonic acid, 4-hydroxybenzenesulfonic acid, pyridinium4-hydroxybenzenesulfonate, benzenedisulfonic acid, 1-naphthalenesulfonicacid, 4-nitrobenzenesulfonic acid, citric acid, benzoic acid, andhydroxybenzoic acid.

Examples of thermal acid generators include K-PURE [registeredtrademark] CXC-1612, K-PURE CXC-1614, K-PURE TAG-2172, K-PURE TAG-2179,K-PURE TAG-2678, K-PURE TAG2689 (each of which is manufactured by KingIndustries, Inc.), and SI-45, SI-60, SI-80, SI-100, SI-110, SI-150 (eachof which is manufactured by Sanshin Chemical Industry Co., Ltd.).

These crosslinking catalysts may be used each alone or in combination.Further, as the basic compound, an amine compound or an ammoniumhydroxide compound may be used, and, as the compound capable ofgenerating a base due to heat, urea may be used.

Examples of amine compounds include tertiary amines, such astriethanolamine, tributanolamine, trimethylamine, triethylamine,trinormalpropylamine, triisopropylamine, trinormalbutylamine,tri-tert-butylamine, trinormaloctylamine, triisopropanolamine,phenyldiethanolamine, stearyldiethanolamine, and diazabicyclooctane, andaromatic amines, such as pyridine and 4-dimethylaminopyridine. Furtherexamples of amine compounds include primary amines, such as benzylamineand normalbutylamine, and secondary amines, such as diethylamine anddinormalbutylamine. These amine compounds may be used each alone or incombination.

Examples of ammonium hydroxide compounds include tetramethylammoniumhydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide,tetrabutylammonium hydroxide, benzyltrimethylammonium hydroxide,benzyltriethylammonium hydroxide, cetyltrimethylammonium hydroxide,phenyltrimethylammonium hydroxide, and phenyltriethylammonium hydroxide.

As the compound capable of generating a base due to heat, for example, acompound which has a thermally unstable group, such as an amide group,an urethane group, or an aziridine group, so that it forms an amine byheating it, may be used. Further examples of the compounds capable ofgenerating a base due to heat include urea, benzyltrimethylammoniumchloride, benzyltriethylammonium chloride, benzyldimethylphenylammoniumchloride, benzyldodecyldimethylammonium chloride, benzyltributylammoniumchloride, and choline chloride.

When the protective film forming composition contains a crosslinkingcatalyst, the amount of the crosslinking catalyst contained ranges0.0001 to 20% by weight, preferably 0.01 to 15% by weight, furtherpreferably 0.1 to 10% by mass, based on the weight of the solid of theprotective film forming composition.

Surfactant

The protective film forming composition of the present invention maycontain, as an optional component, a surfactant for improving theapplication properties with respect to a semiconductor substrate.Examples of the surfactants include nonionic surfactants, e.g.,polyoxyethylene alkyl ethers, such as polyoxyethylene lauryl ether,polyoxyethylene stearyl ether, polyoxyethylene cetyl ether, andpolyoxyethylene oleyl ether; polyoxyethylene alkyl aryl ethers, such aspolyoxyethylene octyl phenyl ether and polyoxyethylene nonyl phenylether; polyoxyethylene-polyoxypropylene block copolymers; sorbitan fattyacid esters, such as sorbitan monolaurate, sorbitan monopalmitate,sorbitan monostearate, sorbitan monooleate, sorbitan trioleate, andsorbitan tristearate; and polyoxyethylene sorbitan fatty acid esters,such as polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitanmonopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylenesorbitan trioleate, and polyoxyethylene sorbitan tristearate, fluorinesurfactants, such as EFTOP [registered trademark] EF301, EFTOP EF303,EFTOP EF352 (manufactured by Mitsubishi Materials Electronic ChemicalsCo., Ltd.), MEGAFACE [registered trademark] F171, MEGAFACE F173,MEGAFACE R-30, MEGAFACE R-30N, MEGAFACE R-40, MEGAFACE R-40-LM(manufactured by DIC Corporation), Fluorad FC430, Fluorad FC431(manufactured by Sumitomo 3M), and AsahiGuard [registered trademark]AG710, Surflon [registered trademark] S-382, Surflon SC101, SurflonSC102, Surflon SC103, Surflon SC104, Surflon SC105, Surflon SC106(manufactured by Asahi Glass Co., Ltd.), and organosiloxane polymerKP341 (manufactured by Shin-Etsu Chemical Co., Ltd.). These surfactantsmay be used each alone or in combination. When the protective filmforming composition contains a surfactant, the amount of the surfactantcontained ranges 0.0001 to 10% by weight, preferably 0.01 to 5% byweight, based on the weight of the solid of the protective film formingcomposition.

Solvent

The protective film forming composition of the present invention may beprepared by dissolving the above-mentioned components in an organicsolvent, and is used in a uniform solution state.

With respect to the solvent for the protective film forming compositionof the present invention, there is no particular limitation as long asit is a solvent which can dissolve therein the compound containing inthe molecule thereof at least a pair of two hydroxy groups adjacent toeach other, or a polymer thereof, and any of such solvents may be used.Particularly, the protective film forming composition of the presentinvention is used in a uniform solution state, and therefore, taking theapplication properties of the composition into consideration, it isrecommended that a solvent generally used in a lithography processshould be used.

Examples of the organic solvents include ethylene glycol monomethylether, ethylene glycol monoethyl ether, methyl cellosolve acetate, ethylcellosolve acetate, diethylene glycol monomethyl ether, diethyleneglycol monoethyl ether, propylene glycol, propylene glycol monomethylether, propylene glycol monoethyl ether, propylene glycol monomethylether acetate, propylene glycol propyl ether acetate, toluene, xylene,methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone,cyclohexanone, cycloheptanone, 4-methyl-2-pentanol, methyl2-hydroxyisobutyrate, ethyl 2-hydroxyisobutyrate, ethyl ethoxyacetate,2-hydroxyethyl acetate, methyl 3-methoxypropionate, ethyl3-methoxypropionate, ethyl 3-ethoxypropionate, methyl3-ethoxypropionate, methyl pyruvate, ethyl pyruvate, ethyl acetate,butyl acetate, ethyl lactate, butyl lactate, 2-heptanone,methoxycyclopentane, anisole, γ-butyrolactone, N-methylpyrrolidone,N,N-dimethylformamide, and N,N-dimethylacetamide. These solvents may beused each alone or in combination.

Of these solvents, preferred are propylene glycol monomethyl ether,propylene glycol monomethyl ether acetate, ethyl lactate, butyl lactate,and cyclohexanone. Especially preferred are propylene glycol monomethylether and propylene glycol monomethyl ether acetate.

Other Components

In the protective film forming composition of the present invention, forexample, a light absorber, a rheology modifier, or a bonding auxiliarymay be added. The rheology modifier is effective in improving thefluidity of the protective film forming composition. The bondingauxiliary is effective in improving the adhesion between a semiconductorsubstrate or a resist and the resist underlying film.

With respect to the light absorber, for example, a commerciallyavailable light absorber described in “Kougyo-you Shikiso no Gijutsu toShijou (Techniques and Markets of Industrial Dyes)” (CMC Publishing Co.,Ltd.) or “Senryo Binran (Dye Handbook)” (edited by The Society ofSynthetic Organic Chemistry, Japan), for example, C. I. Disperse Yellow1, 3, 4, 5, 7, 8, 13, 23, 31, 49, 50, 51, 54, 60, 64, 66, 68, 79, 82,88, 90, 93, 102, 114, and 124; C. I. Disperse Orange 1, 5, 13, 25, 29,30, 31, 44, 57, 72, and 73; C. I. Disperse Red 1, 5, 7, 13, 17, 19, 43,50, 54, 58, 65, 72, 73, 88, 117, 137, 143, 199, and 210; C. I. DisperseViolet 43; C. I. Disperse Blue 96; C. I. Fluorescent Brightening Agent112, 135, and 163; C. I. Solvent Orange 2 and 45; C. I. Solvent Red 1,3, 8, 23, 24, 25, 27, and 49; C. I. Pigment Green 10; and C. I. PigmentBrown 2 may be preferably used. The light absorber is incorporatedgenerally in an amount of 10% by mass or less, preferably 5% by mass orless, based on the mass of the solid of the protective film formingcomposition.

A rheology modifier is added mainly for the purpose of improving thefluidity of the protective film forming composition, particularly forimproving the uniformity of the thickness of the resist underlying filmor the filling of the inside of hole with the protective film formingcomposition in the baking step. Specific examples of rheology modifiersinclude phthalic acid derivatives, such as dimethyl phthalate, diethylphthalate, diisobutyl phthalate, dihexyl phthalate, and butylisodecylphthalate; adipic acid derivatives, such as dinormalbutyl adipate,diisobutyl adipate, diisooctyl adipate, and octyldecyl adipate; maleicacid derivatives, such as dinormalbutyl maleate, diethyl maleate, anddinonyl maleate; oleic acid derivatives, such as methyl oleate, butyloleate, and tetrahydrofurfuryl oleate; and stearic acid derivatives,such as normalbutyl stearate and glyceryl stearate. The rheologymodifier is incorporated generally in an amount of less than 30% bymass, based on the mass of the solid of the protective film formingcomposition.

A bonding auxiliary is added mainly for the purpose of improving theadhesion between a substrate or a resist and the protective film formingcomposition to prevent the resist from peeling off particularly in thedevelopment. Specific examples of bonding auxiliaries includechlorosilanes, such as trimethylchlorosilane,dimethylmethylolchlorosilane, methyldiphenylchlorosilane, andchloromethyldimethylchlorosilane; alkoxysilanes, such astrimethylmethoxysilane, dimethyldiethoxysilane, methyldimethoxysilane,dimethylmethylolethoxysilane, diphenyldimethoxysilane, andphenyltriethoxysilane; silazanes, such as hexamethyldisilazane,N,N′-bis(trimethylsilyl)urea, dimethyltrimethylsilylamine, andtrimethylsilylimidazole; silanes, such as methyloltrichlorosilane,γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, andγ-glycidoxypropyltrimethoxysilane; heterocyclic compounds, such asbenzotriazole, benzimidazole, indazole, imidazole,2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenzoxazole,urazole, thiouracil, mercaptoimidazole, and mercaptopyrimidine; and ureaor thiourea compounds, such as 1,1-dimethylurea and 1,3-dimethylurea.The bonding auxiliary is incorporated generally in an amount of lessthan 5% by mass, preferably less than 2% by mass, based on the mass ofthe solid of the protective film forming composition.

Protective Film Forming Composition

The protective film forming composition of the present inventiongenerally has a solid content of 0.1 to 70% by mass, preferably 0.1 to60% by mass. The solid content indicates a content of the solidremaining after removing the solvent from the all components of theprotective film forming composition. The proportion of the polymer inthe solid ranges 1 to 100% by mass, 1 to 99.9% by mass, 50 to 99.9% bymass, 50 to 95% by mass, and 50 to 90% by mass with increasingpreference.

Method for Producing a Substrate Having a Resist Pattern and Method forProducing a Semiconductor Device

Hereinbelow, a method for producing a substrate having a resist patternand a method for producing a semiconductor device, each using theprotective film forming composition of the present invention, will bedescribed.

The substrate having a resist pattern in the present invention may beproduced by applying the above-described protective film formingcomposition onto a semiconductor substrate and baking the appliedcomposition.

Examples of semiconductor substrates to which the protective filmforming composition of the present invention is applied include asilicon wafer, a germanium wafer, and compound semiconductor wafers,such as gallium arsenide, indium phosphide, gallium nitride, indiumnitride, and aluminum nitride.

When a semiconductor substrate having an inorganic film formed on thesurface thereof is used, the inorganic film is formed by, for example,an ALD (atomic layer deposition) method, a CVD (chemical vapordeposition) method, a reactive sputtering method, an ion plating method,a vacuum deposition method, or a spin coating method (spin on glass:SOG). Examples of the inorganic films include a polysilicon film, asilicon oxide film, a silicon nitride film, a BPSG (Boro-PhosphoSilicate Glass) film, a titanium nitride film, a titanium nitride oxidefilm, a tungsten film, a gallium nitride film, and a gallium arsenidefilm.

The protective film forming composition of the present invention isapplied onto the above-mentioned semiconductor substrate by anappropriate application method, such as a spinner or a coater. Then, theapplied composition is baked using a heating means, such as a hotplate,to form a protective film. The conditions for baking are appropriatelyselected from those at a baking temperature of 100 to 400° C. for abaking time of 0.3 to 60 minutes. Preferred conditions for baking arethose at a baking temperature of 120 to 350° C. for a baking time of 0.5to 30 minutes, and more preferred conditions are those at a bakingtemperature of 150 to 300° C. for a baking time of 0.8 to 10 minutes.The thickness of the formed protective film ranges, for example, 0.001to 10 μm, preferably 0.002 to 1 μm, more preferably 0.005 to 0.5 μm.When the temperature during the baking is lower than the above range, itis likely that crosslinking unsatisfactorily proceeds, making itdifficult to obtain a resistance of the formed protective film to aresist solvent or a basic aqueous hydrogen peroxide solution. To thecontrary, when the temperature during the baking is higher than theabove range, the resultant protective film is likely to sufferdecomposition due to heat.

Exposure through a mask (reticle) for forming a predetermined pattern isconducted, and, for example, an i-line, a KrF excimer laser, an ArFexcimer laser, an EUV (extreme ultraviolet light), or an EB (electronbeam) is used. In development, an alkaline developer is used, and theconditions are appropriately selected from those at a developmenttemperature of 5 to 50° C. for a development time of 10 to 300 seconds.A usable alkaline developer includes, for example, an aqueous solutionof an alkali, e.g., an inorganic alkali, such as sodium hydroxide,potassium hydroxide, sodium carbonate, sodium silicate, sodiummetasilicate, or aqueous ammonia; a primary amine, such as ethylamine orn-propylamine; a secondary amine, such as diethylamine ordi-n-butylamine; a tertiary amine, such as triethylamine ormethyldiethylamine; an alcohol amine, such as dimethylethanolamine ortriethanolamine; a quaternary ammonium salt, such as tetramethylammoniumhydroxide, tetraethylammonium hydroxide, or choline; or a cyclic amine,such as pyrrole or piperidine. Further, the above-mentioned aqueousalkali solution which has added thereto an alcohol, such as isopropylalcohol, or a surfactant, such as a nonionic surfactant, in anappropriate amount, may also be used. Of these, a preferred developer isa quaternary ammonium salt, and further preferred aretetramethylammonium hydroxide and choline. Further, for example, asurfactant may be added to the above developer. Instead of the methodusing an alkaline developer, there may be used a method in whichdevelopment is conducted using an organic solvent, such as butylacetate, to develop a portion of the photoresist in which the alkalidissolution rate is not improved.

Then, using the formed resist pattern as a mask, the protective film issubjected to dry etching. In this instance, when the above-mentionedinorganic film is formed on the surface of the semiconductor substrateused, the surface of the inorganic film is exposed, and, when theinorganic film is not formed on the surface of the semiconductorsubstrate used, the surface of the semiconductor substrate is exposed.

Further, using the protective film obtained after dry etching (includingthe resist pattern in the case where the resist pattern remains on theprotective film) as a mask, the resultant substrate is subjected to wetetching using a wet etching liquid for semiconductor, forming a desiredpattern.

With respect to the wet etching liquid for semiconductor, a generalchemical liquid for etching a wafer for semiconductor may be used, and,for example, any of a substance exhibiting acidic properties and asubstance exhibiting basic properties may be used.

Examples of substances exhibiting acidic property include hydrogenperoxide, hydrofluoric acid, ammonium fluoride, acidic ammoniumfluoride, ammonium hydrogenfluoride, buffered hydrofluoric acid,hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, and amixture thereof.

Examples of substances exhibiting basic property include a basic aqueoushydrogen peroxide solution obtained by mixing ammonia, sodium hydroxide,potassium hydroxide, sodium cyanide, potassium cyanide, or an organicamine, such as triethanolamine, with an aqueous hydrogen peroxidesolution so that the pH of the resultant solution becomes on the basicside. A specific example includes SC-1 (ammonia-hydrogen peroxidesolution). In addition, as a chemical liquid for wet etching, there maybe used a mixture of an aqueous hydrogen peroxide solution and asubstance capable of making the pH be on the basic side, for example,urea such that the mixture is heated to cause urea to suffer thermaldecomposition, generating ammonia, so that the pH of the resultantsolution is eventually on the basic side.

Among these, preferred is an acidic aqueous hydrogen peroxide solutionor a basic aqueous hydrogen peroxide solution, and especially preferredis a basic aqueous hydrogen peroxide solution.

These chemical liquids may contain an additive, such as a surfactant.

The temperature at which the wet etching liquid for semiconductor isused ranges desirably 25 to 90° C., further desirably 40 to 80° C. Thewet etching time ranges desirably 0.5 to 30 minutes, further desirably 1to 20 minutes.

EXAMPLES

Hereinbelow, the present invention will be described in more detail withreference to the following Examples and others, which should not beconstrued as limiting the scope of the present invention.

The apparatus and other conditions used in the measurement of the weightaverage molecular weight of the polymers obtained in the followingsynthesis Examples are shown below.

-   Apparatus: HLC-8320GPC, manufactured by Tosoh Corp.-   GPC Column: Shodex [registered trademark]-Asahipak [registered    trademark] (Showa Denko K.K.)-   Column temperature: 40° C.-   Flow rate: 0.6 mL/minute-   Eluent: N,N-Dimethylformamide (DMF)-   Standard sample: Polystyrene (Tosoh Corp.)

Example 1

A solution containing 7.00 g of glycerol monomethacrylate (product name:BLEMMER GLM, manufactured by NOF Corporation), 2.01 g of methyl2,2′-azobisisobutyrate, and 28.84 g of propylene glycol monomethyl etherwas placed in a dropping funnel. The solution was dropwise added to areaction flask containing therein 7.21 g of propylene glycol monomethylether in a nitrogen gas atmosphere at 100° C., and the resultant mixturewas heated while stirring for 17 hours. To the resultant solution wereadded 9 g of a cation-exchange resin (product name: Dowex [registeredtrademark] 550A, Muromachi Technos Co., Ltd.) and 9 g of ananion-exchange resin (product name: Amberlite [registered trademark]15JWET, Organo Corporation), and the solution was subjected toion-exchange treatment at room temperature for 4 hours. The ion-exchangeresins were separated to obtain a solution of a resin which correspondsto formula (X-1). The resin had a weight average molecular weight Mw of3,400, as determined by GPC using a conversion calibration curveobtained from the standard polystyrene.

To 5.18 g of the obtained resin solution (having a solid content of15.9% by weight) were added 0.21 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.02 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 8.20 g of propylene glycolmonomethyl ether, and 1.40 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Example 2

To 5.18 g of the solution of the resin which corresponds to formula(X-1) (having a solid content of 15.90% by weight) were added 0.05 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation; fluorine surfactant), 7.27 g ofpropylene glycol monomethyl ether, and 1.40 g of propylene glycolmonomethyl ether acetate to prepare a protective film formingcomposition in the form of a solution.

Example 3

A solution containing 6.00 g of glycerol monomethacrylate (product name:BLEMMER GLM, manufactured by NOF Corporation), 3.75 g of methylmethacrylate, 0.62 g of 2,2′-azobis(isobutyronitrile), and 33.17 g ofpropylene glycol monomethyl ether was placed in a dropping funnel. Thesolution was dropwise added to a reaction flask containing therein 8.29g of propylene glycol monomethyl ether in a nitrogen gas atmosphere at100° C., and the resultant mixture was heated while stirring for 17hours. To the resultant solution were added 10 g of a cation-exchangeresin (product name: Dowex [registered trademark] 550A, MuromachiTechnos Co., Ltd.) and 10 g of an anion-exchange resin (product name:Amberlite [registered trademark] 15JWET, Organo Corporation), and thesolution was subjected to ion-exchange treatment at room temperature for4 hours. The ion-exchange resins were separated to obtain a solution ofa resin which corresponds to formula (X-2). The resin had a weightaverage molecular weight Mw of 9,900, as determined by GPC using aconversion calibration curve obtained from the standard polystyrene.

To 6.27 g of the obtained resin solution (having a solid content of17.49% by weight) were added 0.27 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.03 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 11.56 g of propylene glycolmonomethyl ether, and 1.86 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Example 4

To 7.62 g of the solution of the resin which corresponds to formula(X-2) (having a solid content of 17.49% by weight) were added 0.07 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation; fluorine surfactant), 10.46 g ofpropylene glycol monomethyl ether, and 1.86 g of propylene glycolmonomethyl ether acetate to prepare a protective film formingcomposition in the form of a solution.

Example 5

A solution containing 4.50 g of glycerol monomethacrylate (product name:BLEMMER GLM, manufactured by NOF Corporation), 6.13 g of polyethyleneglycol monomethacrylate (product name: BLEMMER PE-90, manufactured byNOF Corporation), 0.54 g of 2,2′-azobis(isobutyronitrile), and 35.75 gof propylene glycol monomethyl ether was placed in a dropping funnel.The solution was dropwise added to a reaction flask containing therein8.94 g of propylene glycol monomethyl ether in a nitrogen gas atmosphereat 100° C., and the resultant mixture was heated while stirring for 17hours. To the resultant solution were added 11 g of a cation-exchangeresin (product name: Dowex [registered trademark] 550A, MuromachiTechnos Co., Ltd.) and 11 g of an anion-exchange resin (product name:Amberlite [registered trademark] 15JWET, Organo Corporation), and thesolution was subjected to ion-exchange treatment at room temperature for4 hours. The ion-exchange resins were separated to obtain a solution ofa resin which corresponds to formula (X-3). The resin had a weightaverage molecular weight Mw of 11,500, as determined by GPC using aconversion calibration curve obtained from the standard polystyrene.

To 6.38 g of the obtained resin solution (having a solid content of17.19% by weight) were added 0.27 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.03 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 11.45 g of propylene glycolmonomethyl ether, and 1.86 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Example 6

To 7.75 g of the solution of the resin which corresponds to formula(X-3) (having a solid content of 17.19% by weight) were added 0.07 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation; fluorine surfactant), 10.32 g ofpropylene glycol monomethyl ether, and 1.86 g of propylene glycolmonomethyl ether acetate to prepare a protective film formingcomposition in the form of a solution.

Example 7

A solution containing 9.36 g of 2-carboxyethyl acrylate, 6.50 g ofmethyl methacrylate, 1.25 g of 2,2′-azobis(isobutyronitrile), and 54.74g of propylene glycol monomethyl ether was placed in a dropping funnel.The solution was dropwise added to a reaction flask containing therein13.68 g of propylene glycol monomethyl ether in a nitrogen gasatmosphere at 100° C., and the resultant mixture was heated whilestirring for 17 hours. To 40.00 g of the resultant solution were added2.25 g of glycidol, 0.28 g of ethyltriphenylphosphonium bromide, and10.12 g of propylene glycol monomethyl ether, and the resultant mixturewas heated under reflux while stirring for 21 hours. To the resultantsolution were added 11 g of a cation-exchange resin (product name: Dowex[registered trademark] 550A, Muromachi Technos Co., Ltd.) and 11 g of ananion-exchange resin (product name: Amberlite [registered trademark]15JWET,

Organo Corporation), and the solution was subjected to ion-exchangetreatment at room temperature for 4 hours. The ion-exchange resins wereseparated to obtain a solution of a resin which corresponds to formula(X-4). The resin had a weight average molecular weight Mw of 15,000, asdetermined by GPC using a conversion calibration curve obtained from thestandard polystyrene.

To 5.05 g of the obtained resin solution (having a solid content of16.31% by weight) were added 0.21 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.02 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 5.54 g of propylene glycolmonomethyl ether, and 4.19 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Example 8

To 5.95 g of the solution of the resin which corresponds to formula(X-4) (having a solid content of 16.31% by weight) were added 0.05 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation; fluorine surfactant), 4.81 g ofpropylene glycol monomethyl ether, and 4.19 g of propylene glycolmonomethyl ether acetate to prepare a protective film formingcomposition in the form of a solution.

Example 9

A solution containing 16.00 g of glycidyl methacrylate, 4.53 g of2,2′-azobis(isobutyronitrile), and 65.68 g of propylene glycolmonomethyl ether was placed in a dropping funnel. The solution wasdropwise added to a reaction flask containing therein 16.48 g ofpropylene glycol monomethyl ether in a nitrogen gas atmosphere at 100°C., and the resultant mixture was heated while stirring for 13 hours. To30.00 g of the resultant solution (epoxy value: 676 g/eq) were added3.72 g of α-thioglycerol, 0.32 g of ethyltriphenylphosphonium bromide,and 12.05 g of propylene glycol monomethyl ether, and the resultantmixture was heated under reflux in a nitrogen gas atmosphere whilestirring for 17 hours. To the resultant solution were added 9 g of acation-exchange resin (product name: Dowex [registered trademark] 550A,Muromachi Technos Co., Ltd.) and 9 g of an anion-exchange resin (productname: Amberlite [registered trademark] 15JWET, Organo Corporation), andthe solution was subjected to ion-exchange treatment at room temperaturefor 4 hours. The ion-exchange resins were separated to obtain a solutionof a resin which corresponds to formula (X-5). The resin had a weightaverage molecular weight Mw of 9,700, as determined by GPC using aconversion calibration curve obtained from the standard polystyrene.

To 5.80 g of the obtained resin solution (having a solid content of18.93% by weight) were added 0.27 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.03 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 12.04 g of propylene glycolmonomethyl ether, and 1.86 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Example 10

To 7.04 g of the solution of the resin which corresponds to formula(X-5) (having a solid content of 18.93% by weight) were added 0.07 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation; fluorine surfactant), 11.04 g ofpropylene glycol monomethyl ether, and 1.86 g of propylene glycolmonomethyl ether acetate to prepare a protective film formingcomposition in the form of a solution.

Comparative Example 1

A solution containing 16.00 g of 2-hydroxyethyl methacrylate, 1.18 g of2,2′-azobis(isobutyronitrile), and 54.98 g of propylene glycolmonomethyl ether was placed in a dropping funnel. The solution wasdropwise added to a reaction flask containing therein 13.75 g ofpropylene glycol monomethyl ether in a nitrogen gas atmosphere at 100°C., and the resultant mixture was heated while stirring for 21 hours. Tothe resultant solution were added 17 g of a cation-exchange resin(product name: Dowex [registered trademark] 550A, Muromachi Technos Co.,Ltd.) and 17 g of an anion-exchange resin (product name: Amberlite[registered trademark] 15JWET, Organo Corporation), and the solution wassubjected to ion-exchange treatment at room temperature for 4 hours. Theion-exchange resins were separated to obtain a solution of a resin whichcorresponds to formula (Y-1). The resin had a weight average molecularweight Mw of 6,800, as determined by GPC using a conversion calibrationcurve obtained from the standard polystyrene.

To 4.63 g of the obtained resin solution (having a solid content of17.76% by weight) were added 0.21 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.02 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 5.95 g of propylene glycolmonomethyl ether, and 4.19 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Comparative Example 2

To 7.36 g of the solution of the resin which corresponds to formula(Y-1) (having a solid content of 17.76% by weight) were added 0.07 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation; fluorine surfactant), 6.99 g ofpropylene glycol monomethyl ether, and 5.59 g of propylene glycolmonomethyl ether acetate to prepare a protective film formingcomposition in the form of a solution.

Comparative Example 3

A solution containing 6.50 g of 2-hydroxyethyl methacrylate, 5.00 g ofmethyl methacrylate, 0.96 g of 2,2′-azobis(isobutyronitrile), and 39.87g of propylene glycol monomethyl ether was placed in a dropping funnel.The solution was dropwise added to a reaction flask containing therein9.97 g of propylene glycol monomethyl ether in a nitrogen gas atmosphereat 100° C., and the resultant mixture was heated while stirring for 17hours. To the resultant solution were added 12 g of a cation-exchangeresin (product name: Dowex [registered trademark] 550A, MuromachiTechnos Co., Ltd.) and 12 g of an anion-exchange resin (product name:Amberlite [registered trademark] 15JWET, Organo Corporation), and thesolution was subjected to ion-exchange treatment at room temperature for4 hours. The ion-exchange resins were separated to obtain a solution ofa resin which corresponds to formula (Y-2). The resin had a weightaverage molecular weight Mw of 4,900, as determined by GPC using aconversion calibration curve obtained from the standard polystyrene.

To 4.60 g of the obtained resin solution (having a solid content of17.88% by weight) were added 0.21 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.02 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 5.99 g of propylene glycolmonomethyl ether, and 4.19 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Comparative Example 4

To 7.45 g of the solution of the resin which corresponds to formula(Y-2) (having a solid content of 17.88% by weight) were added 0.07 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation;

fluorine surfactant), 6.90 g of propylene glycol monomethyl ether, and5.58 g of propylene glycol monomethyl ether acetate to prepare aprotective film forming composition in the form of a solution.

Comparative Example 5

A solution containing 14.00 g of 4-hydroxyphenyl methacrylate (productname: PQMA, manufactured by Showa Denko K.K.), 1.13 g of2,2′-azobis(isobutyronitrile), and 42.37 g of propylene glycolmonomethyl ether was placed in a dropping funnel. The solution wasdropwise added to a reaction flask containing therein 18.16 g ofpropylene glycol monomethyl ether in a nitrogen gas atmosphere at 100°C., and the resultant mixture was heated while stirring for 14 hours. Tothe resultant solution were added 15 g of a cation-exchange resin(product name: Dowex [registered trademark] 550A, Muromachi Technos Co.,Ltd.) and 15 g of an anion-exchange resin (product name: Amberlite[registered trademark] 15JWET, Organo Corporation), and the solution wassubjected to ion-exchange treatment at room temperature for 4 hours. Theion-exchange resins were separated to obtain a solution of a resin whichcorresponds to formula (Y-3). The resin had a weight average molecularweight Mw of 11,000, as determined by GPC using a conversion calibrationcurve obtained from the standard polystyrene.

To 4.47 g of the obtained resin solution (having a solid content of18.41% by weight) were added 0.21 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.02 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 6.12 g of propylene glycolmonomethyl ether, and 4.19 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Comparative Example 6

To 7.24 g of the solution of the resin which corresponds to formula(Y-3) (having a solid content of 18.41% by weight) were added 0.07 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation; fluorine surfactant), 7.12 g ofpropylene glycol monomethyl ether, and 5.58 g of propylene glycolmonomethyl ether acetate to prepare a protective film formingcomposition in the form of a solution.

Comparative Example 7

To 0.82 g of polyparahydroxystyrene (product name: VP-8000, manufacturedby Nippon Soda Co., Ltd.) were added 0.21 g oftetramethoxymethylglycoluril (product name: POWDERLINK [registeredtrademark] 1174, manufactured by Nihon Cytec Industries Inc.) as acrosslinking agent, 0.03 g of pyridinium p-toluenesulfonate as acrosslinking acid catalyst, 0.001 g of a surfactant (product name:MEGAFACE [trade name] R-40, manufactured by DIC Corporation; fluorinesurfactant), 9.77 g of propylene glycol monomethyl ether, and 4.19 g ofpropylene glycol monomethyl ether acetate to prepare a protective filmforming composition in the form of a solution.

Comparative Example 8

To 1.33 g of polyparahydroxystyrene (product name: VP-8000, manufacturedby Nippon Soda Co., Ltd.) were added 0.07 g of pyridiniumtrifluoromethanesulfonate as a crosslinking acid catalyst, 0.001 g of asurfactant (product name: MEGAFACE [trade name] R-40, manufactured byDIC Corporation; fluorine surfactant), 13.02 g of propylene glycolmonomethyl ether, and 5.58 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Comparative Example 9

A solution containing 16.00 g of glycidyl methacrylate, 4.53 g of2,2′-azobis(isobutyronitrile), and 65.68 g of propylene glycolmonomethyl ether was placed in a dropping funnel. The solution wasdropwise added to a reaction flask containing therein 16.48 g ofpropylene glycol monomethyl ether in a nitrogen gas atmosphere at 100°C., and the resultant mixture was heated while stirring for 13 hours. To30.00 g of the resultant solution (epoxy value: 676 g/eq) were added5.31 g of 3,4-dihydroxybenzoic acid, 0.20 g of benzyltriethylammoniumchloride, and 17.89 g of propylene glycol monomethyl ether, and theresultant mixture was heated under reflux in a nitrogen gas atmospherewhile stirring for 20 hours. To the resultant solution were added 11 gof a cation-exchange resin (product name: Dowex [registered trademark]550A, Muromachi Technos Co., Ltd.) and 11 g of an anion-exchange resin(product name: Amberlite [registered trademark] 15JWET, OrganoCorporation), and the solution was subjected to ion-exchange treatmentat room temperature for 4 hours. The ion-exchange resins were separatedto obtain a solution of a resin which corresponds to formula (Y-4). Theresin had a weight average molecular weight Mw of 24,400, as determinedby GPC using a conversion calibration curve obtained from the standardpolystyrene.

To 4.22 g of the obtained resin solution (having a solid content of19.51% by weight) were added 0.21 g of tetramethoxymethylglycoluril(product name: POWDERLINK [registered trademark] 1174, manufactured byNihon Cytec Industries Inc.) as a crosslinking agent, 0.03 g ofpyridinium p-toluenesulfonate as a crosslinking acid catalyst, 0.001 gof a surfactant (product name: MEGAFACE [trade name] R-40, manufacturedby DIC Corporation; fluorine surfactant), 9.12 g of propylene glycolmonomethyl ether, and 1.40 g of propylene glycol monomethyl etheracetate to prepare a protective film forming composition in the form ofa solution.

Comparative Example 10

To 6.83 g of the solution of the resin which corresponds to formula(Y-4) (having a solid content of 19.51% by weight) were added 0.07 g ofpyridinium trifluoromethanesulfonate as a crosslinking acid catalyst,0.001 g of a surfactant (product name: MEGAFACE [trade name] R-40,manufactured by DIC Corporation; fluorine surfactant), 11.24 g ofpropylene glycol monomethyl ether, and 1.86 g of propylene glycolmonomethyl ether acetate to prepare a protective film formingcomposition in the form of a solution.

Test for Resist Solvent Resistance

Each of the protective film forming compositions prepared in Examples 1to 10 and Comparative Examples 1 to 10 was applied onto a silicon waferusing a spin coater (spin coating). After the application, the siliconwafer was heated on a hotplate at 215° C. for one minute to form a film(protective film) having a thickness of 200 nm. Then, for evaluating theresist solvent resistance of the protective film, the silicon waferhaving the protective film formed thereon was immersed in a mixedsolvent of propylene glycol monomethyl ether and propylene glycolmonomethyl ether acetate in a weight ratio of 7:3 for one minute,subjected to spin drying and then baked at 100° C. for 30 seconds. Thethickness of the protective film before and after the immersion in themixed solvent was measured by means of an interference thickness meter.A resist solvent resistance was evaluated as follows. From the equation((Thickness of the film before the immersion in the solvent)−(Thicknessof the film after the immersion in the solvent))÷(Thickness of the filmbefore the immersion in the solvent)×100, the thickness reduction ratio(%) of the protective film removed by immersion in the solvent wascalculated to evaluate the resist solvent resistance. A thicknessreduction ratio of about 1% or less is in the acceptable range.

TABLE 1 Example Thickness reduction ratio Example 1  0.3% Example 2 0.0% Example 3  0.1% Example 4  0.4% Example 5  0.2% Example 6  0.1%Example 7  0.2% Example 8  0.4% Example 9  0.0% Example 10  0.0%Comparative Example 1  0.0% Comparative Example 2  0.1% ComparativeExample 3  0.3% Comparative Example 4  0.8% Comparative Example 5  0.4%Comparative Example 6 97.5% Comparative Example 7  0.2% ComparativeExample 8 98.1% Comparative Example 9  0.0% Comparative Example 10  0.2%

As apparent from the above results, the films in Examples 1 to 10exhibited so excellent resist solvent resistance that, after the filmwas immersed in the resist solvent, the change of the thickness was verysmall. In contrast, the films in Comparative Examples 6 and 10 exhibitedan unsatisfactory resist solvent resistance such that, after immersed inthe resist solvent, the film was removed. Thus, the films in Examples 1to 10 advantageously exhibit a resist solvent resistance, and have sucha satisfactory resist solvent resistance that the film may function as aprotective film.

Test for Resistance to a Basic Aqueous Hydrogen Peroxide Solution

The resistance to a basic aqueous hydrogen peroxide solution wasevaluated as follows. Each of the protective film forming compositionsprepared in Examples 1 to 10 and Comparative Examples 1 to 5, 7, 9, and10, which exhibited excellent resist solvent resistance in theabove-mentioned test for resist solvent resistance, was applied to a 50nm-thick TiN deposited substrate, and heated at 215° C. for one minuteto form a film having a thickness of 200 nm. Thereafter, a basic aqueoushydrogen peroxide solution was prepared by mixing 28% aqueous ammonia,33% hydrogen peroxide, and water in a weight ratio of 1:1:2. The TiNdeposited substrate having the protective film forming compositionapplied thereto was immersed in the prepared basic aqueous hydrogenperoxide solution heated to 50° C., and the period of time required forpeeling off the protective film from the substrate from the timeimmediately after the immersion of the substrate in the solution wasmeasured. The results are shown in Table 2.

TABLE 2 Example Time required for peeling Example 1  76 Seconds Example2  55 Seconds Example 3  67 Seconds Example 4  46 Seconds Example 5  55Seconds Example 6  46 Seconds Example 7  47 Seconds Example 8  34Seconds Example 9 197 Seconds Example 10 384 Seconds Comparative Example1  15 Seconds Comparative Example 2  16 Seconds Comparative Example 3  7 Seconds Comparative Example 4  18 Seconds Comparative Example 5  15Seconds Comparative Example 7  11 Seconds Comparative Example 9 344Seconds Comparative Example 10 281 Seconds

As apparent from the above results, when immersed in the basic aqueoushydrogen peroxide solution, the films in Examples 1 to 10 were unlikelyto be peeled off from the substrate, as compared to the films inComparative Examples 1 to 5 and 7. That is, the films in Examples 1 to10 exhibited a higher chemical resistance to the basic aqueous hydrogenperoxide solution than that in Comparative Examples 1 to 5 and 7, andthus are advantageously used as a protective film against a basicaqueous hydrogen peroxide solution.

Evaluation of Etching Selective Ratio

The etching selective ratio was evaluated as follows. Each of theprotective film forming compositions prepared above in Examples 2, 4, 6,8, and 10 and Comparative Example 10 was applied onto a silicon wafer,and heated at 215° C. for one minute to form a film having a thicknessof 200 nm. Then, the formed protective film and a resist film obtainedfrom a resist solution, manufactured by Sumitomo Chemical Co., Ltd.(product name: SUMIRESIST PAR855), were subjected to dry etching by amixed gas of oxygen and nitrogen using a dry etching machine (RIE-10NR),manufactured by Samco Inc., to measure the dry etching rate ratio of theprotective film to the resist (selective ratio of the dry etching rate).The etching selective ratio is shown in Table 3.

TABLE 3 Example Dry etching selective ratio (Resist ratio) Example 21.54 Example 4 1.39 Example 6 1.34 Example 8 1.23 Example 10 1.30Comparative Example 10 1.10

As apparent from the above results, the films in Examples 2, 4, 6, 8,and 10 have a high dry etching selective ratio, as compared to the filmin Comparative Example 10. That is, the films in Examples 2, 4, 6, 8,and 10 have a faster dry etching rate than that in Comparative Example10, can provide a reduced dry etching time needed for removing theprotective film, and thus can advantageously reduce any damage to thesubstrate.

INDUSTRIAL APPLICABILITY

In the present invention, there can be provided a composition forforming a protective film which has both a wet etching mask function(SC-1 resistance) during processing of the substrate and such a fastetching rate (high etch rate) that the film can be quickly removed bydry etching.

1. A composition for forming a protective film against a wet etching liquid for semiconductor, the protective film forming composition comprising a solvent and a compound containing in the molecule thereof at least a pair of two hydroxy groups adjacent to each other, or a polymer thereof.
 2. The protective film forming composition according to claim 1, wherein the two hydroxy groups adjacent to each other constitute a 1,2-ethanediol structure.
 3. The protective film forming composition according to claim 1, wherein the compound has a partial structure represented by the following formula (1) or formula (2):

wherein, in formula (1) and formula (2), each of R¹, R², and R³ represents a hydrogen atom, or an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 40 carbon atoms, each of the groups optionally being substituted, and R¹ and R² or R³ optionally together form a ring, and Z¹ and Z² represent a monovalent organic group.
 4. The protective film forming composition according to claim 3, wherein, in formula (1) and formula (2), R¹, R², and R³ are a hydrogen atom.
 5. The protective film forming composition according to claim 1, further comprising a crosslinking catalyst.
 6. The protective film forming composition according to claim 1, further comprising a crosslinking agent.
 7. The protective film forming composition according to claim 1, further comprising a surfactant.
 8. A protective film which is a baked product of an applied film of the protective film forming composition according to any claim
 1. 9. A method for producing a substrate having a resist pattern, comprising the steps of applying the protective film forming composition according to claim 1 onto a semiconductor substrate and baking the applied composition to form a protective film as a resist underlying film, which is used for producing a semiconductor.
 10. A method for producing a semiconductor device, comprising the steps of: forming a protective film on a semiconductor substrate optionally having an inorganic film formed on the surface thereof using a protective film forming composition according to claim 1; forming a resist pattern on the protective film; subjecting the protective film to dry etching using the formed resist pattern as a mask so as to expose a surface of the inorganic film or the semiconductor substrate; and, using the dry-etched protective film as a mask, subjecting the inorganic film or the semiconductor substrate to wet etching with a wet etching liquid for semiconductor and to washing. 